The present invention relates to an electrically insulating thin-film-forming resin composition, and to a method for forming an electrically insulating thin film. More particularly, it relates to an electrically insulating thin-film-forming resin composition with which it is possible to form an electrically insulating thin film having a low dielectric constant, and to a method for efficiently forming an electrically insulating thin film having a low dielectric constant on the surface of an electronic device.
Examples of a method for forming an electrically insulating thin film on the surface of an electronic device include a method in which the surface of an electronic device is coated with a hydrogen silsesquioxane resin solution, the solvent is evaporated off, and the surface is then heated at 150 to 1000xc2x0 C. (see Japanese Laid-Open Patent Application S63-144525), and a method in which the surface of an electronic device is coated with a solution of a hydrogen silsesquioxane resin and a platinum or rhodium catalyst, the solvent is evaporated off, and the surface is then heated at 150 to 1000xc2x0 C. (see Japanese Laid-Open Patent Application S63-144524).
As miniaturization and integration have increased in electronic devices in recent years, there has been a need for a method for forming an electrically insulating layer with a low dielectric constant. More specifically, there is a need for a method for forming an electrically insulating layer with a low dielectric constant (a specific inductive capacity of less than 2.5) in a highly integrated circuit with a next-generation design rule of 0.15 xcexcm or less. Accordingly, Japanese Laid-Open Patent Application H10-279687 proposes a method in which the surface of an electronic device is coated with a solution composed of a hydrogen silsesquioxane resin and two types of solvent with different boiling points or affinity to the resin, after which part of the solvent is evaporated, and the surface is heated to evaporate the solvent either during or after the crosslinking of the resin, thereby forming a porous electrically insulating crosslinked thin film.
Unfortunately, a porous electrically insulating thin film generally has poor mechanical strength and is susceptible to infiltration and attack by a variety of chemicals, and therefore cannot sufficiently stand up to the next-generation of multilayer wiring processes, and particularly to a copper dual damascene process, making such films impractical. Also, to form an electrically insulating thin film with a low dielectric constant, a relatively large amount of silicon atom-bonded hydrogen atoms must be present in the hydrogen silsesquioxane resin, and consequently the silicon atom-bonded hydrogen atoms in the thin film react due to the heat, various chemicals, or plasma encountered in the various steps following the formation of the thin film, such as the multilayer wiring of an electronic device, which further raises the density of the thin film and drives up the dielectric constant.
It is an object of the present invention to provide an electrically insulating thin-film-forming resin composition with which it is possible to form an electrically insulating thin film having a low dielectric constant, and to a method for efficiently forming an electrically insulating thin film having a low dielectric constant on an electronic device.
The present invention is an electrically insulating thin-film-forming resin composition comprising (A) an inorganic or organic electrically insulating resin having silicon atom-bonded hydrogen atoms, (B) a compound having groups able to react with the silicon atom-bonded hydrogen atoms in component (A) and having a boiling point under atmospheric pressure of at least 250xc2x0 C., and (C) a solvent; and a method for forming an electrically insulating thin film therefrom.